Vaccine responses in ageing and chronic viral infection

Abstract

Over the last few decades, changing population demographics have shown that there are a growing number of individuals living past the age of 60. With this expanding older population comes an increase in individuals that are more susceptible to chronic illness and disease. An important part of maintaining health in this population is through prophylactic vaccination, however, there is growing evidence that vaccines may be less effective in the elderly. Furthermore, with the success of anti-viral therapies, chronic infections such as HIV are becoming increasingly prevalent in older populations and present a relatively unstudied population with respect to the efficacy of vaccination. Here we will examine the evidence for age-associated reduction in antibody and cellular responsiveness to a variety of common vaccines and investigate the underlying causes attributed to this phenomenon, such as inflammation and senescence. We will also discuss the impact of chronic viral infections on immune responses in both young and elderly patients, particularly those living with HIV, and how this affects vaccinations in these populations.

Figure 1:

Dysregulated cellular response to vaccination in elderly individuals. Diagram of cellular response to vaccination in elderly individuals. Flat-head arrows indicate actions that inhibit cellular responses. Cell types are as indicated in the legend. Created with BioRender.

Figure 2:

Impact of HIV infection on antibody production in elderly individuals. Schematic of downstream impacts of HIV on the immune response. Flat-head arrows indicate actions that inhibit disease progression. Purple dots indicate the surrounding cytokine milieu that impacts cellular responses.

Figure 3:

Diagram of impact of age and chronic disease on vaccine response. Elderly and chronically-infected individuals have significantly altered antibody and cellular responses following vaccination compared to those in younger and/or healthy individuals.